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Confidence Intervals =S

  1. Jun 3, 2009 #1
    Hey ladies and gents,
    I have a question that I'm not fully getting.

    An FL Student Survey reprts the results for responses on the number of times a week the subject reads a newspaper:

    Variable : news
    n = 60
    mean = 4.1
    standard deviation = 3.0
    SE mean = 0.387
    95% CI = (3.325-4.875)

    QUESTION: Is it plausible that mu = 7, where mu is the population mean for all Floridian Student? Explain.
    I'm thinking yes, because confdence interval is an estimate of population proportion, and mu is the actual population mean. If this is true, then since we only have 95% confidence, mu could equal 7 because we have 5% that our estimates are incorrect and not between the interval. Yet, if the interval doesn't have 7 in it, how can this be true. I'm confused to this concept.

    As always, the help is highly appreciated!
  2. jcsd
  3. Jun 3, 2009 #2


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    Homework Helper

    I haven't checked the calculations, so I'm basing this response on the assumption that the endpoints of the interval were correctly calculated.

    This interval is an estimate of the population mean , not the proportion as your first sentence states (I'll assume that was a typo). Based on this interval, is it likely that [tex] \mu = 7 [/tex]? No, it isn't, since 7 is not located in the interval.

    Could the true mean be 7? Yes, but it isn't likely to be, for the reason stated above.
  4. Jun 3, 2009 #3
    And yes, meant to say mean, but it was 1 in the morning...
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